Method and apparatus for alphabet input

ABSTRACT

A method and apparatus for inputting letters by combining basic elements obtained by separating and symbolizing strokes of letters, so as to provide excellent letter intuitiveness and recognition. According to the present invention, a letter may be input by pressing one of or sequentially pressing two of keys to which basic elements  ,  ,  ,  ,  ,  ,  , †,  , —, and   obtained by separating and symbolizing strokes of letters are assigned, and letters may be rapidly and conveniently input by minimizing key pressing paths.

CROSS-REFERENCE TO RELATED PATENT APPLICATION

This application claims the benefits of Korean Patent Application No.10-2009-0041250, filed on May 12, 2009, and Korean Patent ApplicationNo. 10-2010-0023489, filed on Mar. 16, 2010 in the Korean IntellectualProperty Office, the disclosures of which are incorporated herein intheir entirety by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method and apparatus for inputtingletters, and more particularly, to a method and apparatus for inputtingletters via a simple manipulation by using a much less number of keysthan the total number of alphabet letters.

2. Description of the Related Art

As well known, English is one of official international languages usedin international conferences, etc., and is being widely used as a secondlanguage in many countries. In English, two or more of twenty sixletters are combined to represent one word having a particular meaning.

On a QWERTY keyboard commonly used for computers or the like, twenty sixletters are respectively assigned to different keys so that a user mayeasily input a desired word or sentence by pressing keys correspondingto the appropriate letters.

Recently, due to the rapid development of electronic technologies,various compact and portable devices such as cellular phones includingsmart phones, Moving Picture Experts Group (MPEG) audio layer 3 (MP3)players, digital multimedia broadcasting (DMB) terminals, satelliteterminals, personal digital assistants (PDAs), and portable multimediaplayers (PMPs) have become very popular. In this regard, as the size ofsuch devices can be the most competitive marketing advantage,manufactures have made continuous efforts to produce thin, light, andcompact portable devices.

As such, portable devices typically have a keypad that contains alimited number of keys, for example, twelve letter keys, and a fewadditional function keys.

FIG. 1 illustrates a conventional phone-key keypad for inputting numbersand English letters.

This type of keypad is common in coded phones, cellular phones, etc.,and is refereed to as a phone-key keypad. In the phone-key keypad, fromamong twenty six letters, letters Q and Z are assigned to key number 1,letters A, B, and C are assigned to key number 2, letters D, E, and Fare assigned to key number 3, letters G, H, and I are assigned to keynumber 4, letters J, K, and L are assigned to key number 5, letters M,N, and 0 are assigned to key number 6, letter P, R, and S are assignedto key number 7, letters T, U, and V are assigned to key number 8, andletters W, X, and Y are assigned to key number 9.

In the phone-key keypad having the above arrangement, a letter is inputby pressing a specific key a certain number of times. For example, if auser desires to input the text “call me john”, the keypad has to bemanipulated as follows: triple pressing of key number 2→(a pause or aspace)→single pressing of key number 2→triple pressing of key number5→(a pause or a space)→triple pressing of key number 5→(a pause)→(aspace)→single pressing of key number 6→double pressing of key number3→(a pause or a space)→a space→single pressing of key number 5→triplepressing of key number 6→double pressing of key number 4→double pressingof key number 6.

In this case, since there is no correlation between the letters assignedto each key and no rule or logic with respect to the number of timesthat a key is pressed to input a specific letter, a user needs to bevery careful when inputting desired letters. Also, an error in pressinga key frequently occurs because a plurality of letters are assigned toone key, and a large amount of time or a larger number of key pressingsis required because a pause or pressing a space key is required. Inorder to solve this problem, Korean Patent Registration No. 10-0672773entitled Alphabet Input Apparatus and Alphabet Input Method andregistered on Dec. 27, 2006 (hereinafter referred to as citedreference 1) discloses a method of separating and symbolizing strokes ofletters to symbolize the strokes and combining the symbols with eachother to input a desired letter.

In cited reference 1, symbols such as /, |, \,

, —,

, V, O, and

are assigned to nine keys and one to four of the symbols are combined toinput a desired letter. The letters are expressed by selecting thesymbols as described below.

A: sequential pressing of /, \, and —

B: sequential pressing of |,

, and ⊂

C: single pressing of ⊂

D: sequential pressing of | and ⊃

E: sequential pressing of |, —, —, and —

F: sequential pressing of |, −, and —

G: sequential pressing of

, —, and |

H: sequential pressing of |, —, and |

I: single pressing of |

J: sequential pressing of | and

K: sequential pressing of |, /, and \

L: sequential pressing of | and —

M: sequential pressing of |, \, /, and |

N: sequential pressing of |, \, and |

O: single pressing of O

P: sequential pressing of | and ⊃

Q: sequential pressing of O and \

R: sequential pressing of |,

, and \

S: sequential pressing of

and ⊃

T: sequential pressing of — and |

U: single pressing of ∪

V: single pressing of V

W: sequential pressing of V and V

X: sequential pressing of \ and /

Y: sequential pressing of V and |

Z: sequential pressing of —, /, and —

Although the apparatus and method disclosed in cited reference 1 areconvenient to input a letter by combining strokes of letters, usersstill have difficulties in using them because some letters requirepressing a key four times and the above keypad assignment is not asinstinctively and easily recognizable as handwriting. In cited reference1, a total of sixty key pressings are required to input all alphabetletters.

SUMMARY OF THE INVENTION

The present invention provides a method and apparatus for inputtingletters, which are capable of increasing user's convenience wheninputting letters by allowing a user to input letters in the same manneras in handwriting direction and order.

According to an aspect of the present invention, there is provided akeypad apparatus for inputting letters, the keypad apparatus comprisinga plurality of keys to which basic elements

,

,

,

,

,

, †,

, —, and

obtained by separating and symbolizing strokes of letters are separatelyassigned, and the keypad apparatus recognizing letters by using a methodcomprising at least one of recognizing sequential pressing of the basicelements

and

as the letter a; recognizing sequential pressing of the basic elements

and

as the letter b; recognizing single pressing of the basic element

as the letter c; recognizing sequential pressing of the basic elements

and

as alphabet d; recognizing single pressing of the basic element — as theletter e; recognizing single pressing of the basic element

as the letter f; recognizing sequential pressing of the basic elements

and

as the letter g; recognizing sequential pressing of the basic elements

and

as the letter h; recognizing single pressing of the basic element

as the letter i; recognizing single pressing of the basic element

as the letter j; recognizing sequential pressing of the basic elements

and

as the letter k; recognizing single pressing of the basic element

as the letter l; recognizing double pressing of the basic element

as the letter m; recognizing single pressing of the basic element

as the letter n; recognizing single pressing of the basic element

as the letter o; recognizing sequential pressing of the basic elements †and

as the letter p; recognizing sequential pressing of the basic elements

and † as the letter q; recognizing sequential pressing of the basicelements

and — as the letter r; recognizing sequential pressing of the basicelements

and

as the letter s; recognizing single pressing of the basic element † asthe letter t; recognizing single pressing of the basic element

as the letter u; recognizing double pressing of the basic element

as the letter v; recognizing double pressing of the basic element

as the letter w; recognizing sequential pressing of the basic elements

and

as the letter x; recognizing sequential pressing of the basic elements

and

as the letter y; and recognizing double pressing of the basic element —as the letter z.

According to the present invention, English letters may be simply andeasily input in the same manner as in handwriting direction and order.

Also, English letters may be intuitively input by pressing keys aminimum number of times and key pressing paths on a keypad may beminimized.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages of the present inventionwill become more apparent by describing in detail exemplary embodimentsthereof with reference to the attached drawings in which:

FIG. 1 illustrates a conventional phone-key keypad for inputting numbersand English letters;

FIGS. 2A through 2C illustrate keypads according to embodiments of thepresent invention;

FIG. 3 shows combinations of basic elements for inputting small letters,according to an embodiment of the present invention;

FIG. 4 is a diagram for describing a method of assigning five main basicelements on a keypad, according to an embodiment of the presentinvention;

FIG. 5 is a diagram for describing a method of assigning the other basicelements on a keypad, according to an embodiment of the presentinvention;

FIG. 6 shows overall key pressing orders for inputting small letters ona keypad, according to an embodiment of the present invention;

FIG. 7 shows overall key dragging orders for inputting small letters ona keypad, according to an embodiment of the present invention;

FIG. 8 illustrates a cellular phone including the keypad illustrated inFIG. 2A, according to an embodiment of the present invention;

FIGS. 9A through 9D illustrate various key assignments of basic elementson a keypad, according to embodiments of the present invention;

FIG. 10 illustrates a keypad for identifying subsequent basic elementsthat are available to be pressed after an initial basic element ispressed, according to an embodiment of the present invention; and

FIG. 11 is a block diagram of a keypad apparatus according to anembodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The attached drawings for illustrating exemplary embodiments of thepresent invention are referred to in order to gain a sufficientunderstanding of the present invention, the merits thereof, and theobjectives accomplished by the implementation of the present invention.

Hereinafter, the present invention will be described in detail byexplaining embodiments of the invention with reference to the attacheddrawings. Like reference numerals denote like elements in the drawings.

In the present application, a keypad includes user interfaces forpressing keys, e.g., a keyboard and a touchscreen.

According to a report regarding the frequency of use of communicationtools in the USA, the number of voice calls has increased by 5% from2007 to 2008, while the usage of short message service (SMS) hasincreased by 300%. People now regard that unidirectional communicationsuch as sending a short message is more attractive than bidirectionalcommunication such as phone calling.

Furthermore, a short text message is more interesting to people than aphone call. In addition, in line with the development of techniques forsending short messages, even competitions have been held for users whorapidly send short messages. Furthermore, as Internet services forcellular phones are currently being developed, a rapid and simple textinput method is highly demanded.

However, an English letter input method for compact devices does notprovide an appropriate solution. The keypad and input method describedabove in relation to FIG. 1 are inconvenient and also inputting letterrequires a long time.

This fundamental problem arises from restriction of the number of keysin a cellular phone keypad where twenty-six letters are assigned totwelve keys. Although some currently commercialized compact devices suchas cellular phones employ a QWERTY keyboard in order to cope with theabove restriction, a physical restriction due to the size of cellularphones still remains. In particular, this restriction is exacerbated inthe case of people who have large fingers.

Accordingly, a new apparatus and method of alphabet input that allowsusers to intuitively recognize keys and to conveniently, rapidly, andeasily input English letters is required.

FIGS. 2A through 2C illustrate keypads according to embodiments of thepresent invention.

Referring to FIG. 2A, basic elements

,

,

,

,

,

,

, †,

, —, and

, which are obtained by separating and symbolizing strokes of letters,are assigned to keypad buttons. English letters input by using theeleven basic elements are basically small letters. Capital letters mayalso be input by changing modes as when using a conventional phone-keykeypad, and the basic elements are displayed on the top right side ofeach key.

The shapes of the basic elements are variable in consideration of user'sconvenience or design of the keypad. For example, the basic element †for inputting the letter t by pressing a single key does not alwaysinclude a horizontal line, and a solid or dotted line may be used as thehorizontal line in consideration of user's convenience. Also, the basicelement

for inputting the letter f may not include a horizontal line asillustrated in FIG. 2A or may include the horizontal line as a dotted orsolid line. Although the horizontal line is not included, there is noproblem for users to intuitively recognize the basic element

as the letter f.

Before describing the keypad illustrated in FIG. 2B, a method ofinputting letters by combining the basic elements illustrated in FIG. 2Awill now be described in detail with reference to FIG. 3 in order toeasily understand the structures of the modified keypads illustrated inFIGS. 2B and 2C.

FIG. 3 shows combinations of the basic elements

,

,

,

,

,

,

, †,

, —, and

for inputting small letters, according to an embodiment of the presentinvention.

Referring to FIG. 3, sequential pressing of

and

is recognized as the letter a, sequential pressing of

and

is recognized as the letter b, single pressing of

is recognized as the letter c, sequential pressing of

and

is recognized as the letter d, single pressing of — is recognized as theletter e, single pressing of

is recognized as the letter f, sequential pressing of

and

is recognized as the letter g, sequential pressing of

and

is recognized as the letter h, single pressing of

 is recognized as the letter i, single pressing of

is recognized as the letter j, sequential pressing of

and

is recognized as the letter k, single pressing of

is recognized as the letter l, double pressing of

is recognized as the letter m, single pressing of

is recognized as the letter n, single pressing of

is recognized as the letter o, sequential pressing of † and

is recognized as the letter p, sequential pressing of

and † is recognized as the letter q, sequential pressing of

and — is recognized as the letter r, sequential pressing of

and

is recognized as the letter s, single pressing of † is recognized as theletter t, single pressing of

is recognized as the letter

,double pressing of

is recognized as the letter v, double pressing of

is recognized as the letter w, sequential pressing of

and

is recognized as the letter x, sequential pressing of

and

is recognized as the letter y, and double pressing of — is recognized asthe letter z.

These combinations may vary in order to increase user's convenience orintuitiveness. For example, sequential pressing of

and — may be recognized as the letter f, double pressing of

may be recognized as the letter s, sequential pressing of — and

may be recognized as the letter t, sequential pressing of

and

, or

and † may be recognized as the letter y, and single pressing of

may be recognized as the letter b.

Also, in order to generate each alphabet letter by double key pressingfor for a unity purpose, an additional key such as a space key (e.g., a# key in FIG. 2) is pressed after a single key is pressed. If double keypressing method is used for each letter and if a key is pressed to inputa letter and then another key is pressed to input another letter, thekeys may be prevented from being combined to input an unintended letter.As such, a time delay due to a pause after a single key is pressed maybe reduced.

However, if a predetermined pause period passes after a single key ispressed, input of a letter recognized by pressing the single key may beconfirmed and thus a subsequent key input may not influence the input ofthe letter generated by a single key.

The method of inputting letters illustrated in FIG. 3 may be implementedas software, and thus may be written in a computer-readable programminglanguage so as to be executed by a terminal device. If the terminaldevice includes a touchpad, the keypad illustrated in FIG. 2A, 2B, or 2may be displayed on the touchpad and thus desired letters may be inputby using the above-described method.

Also, the software may be stored in a computer-readable recordingmedium.

As illustrated in FIG. 3, when children learn how to write, they startto write small letters using as reference a third line from among fourlines. In this case, a short vertical line at a right side of a letteras in the letter a is represented by using the basic element

, a long vertical line from a first line to the third line as in theletter b or d is represented by using the basic element

, and a long vertical line from a second line to a fourth line as in theletter p or q is represented by using the basic element †.

Also, in order to press the basic elements according to the letterwriting direction and order illustrated in FIG. 3, the assignment andalignment of five main basic elements

,

,

,

, and † as illustrated in FIG. 4 are important.

The keypad illustrated in FIG. 2B will now be described. The keypadillustrated in FIG. 2B is a modification of the keypad illustrated inFIG. 2A. In FIG. 2B, the basic elements

,

,

,

,

,

,

, †,

, and —, which are obtained by separating and symbolizing strokes ofletters, are assigned on the keypad. Compared to FIG. 2A, the number ofbasic elements is reduced to ten in FIG. 2B. As in FIG. 2A, Englishletters input by using the ten basic elements are basically smallletters. Capital letters may also be input by changing modes as whenusing a conventional phone-key keypad, and the basic elements aredisplayed on the top side of each key.

The shapes of the basic elements are also variable in consideration ofuser's convenience or design of the keypad. For example, the basicelement † for inputting the letter t by pressing a single key does notalways include a horizontal line, and a solid or dotted line may be usedas the horizontal line in consideration of user's convenience. Also, thebasic element

for inputting the letter f may not include a horizontal line asillustrated in FIG. 2B or may include the horizontal line as a dotted orsolid line. Although the horizontal line is not included, there is noproblem to intuitively recognize the basic element

as the letter f. Also, there is no problem to intuitively recognize thebasic element

 as the letter o or a semicircle of the letter b or p.

Compared to FIG. 2A, single pressing of the basic element

may be recognized as the letter o in the keypad illustrated in FIG. 2B.The rest of the input method is almost the same as the method describedwith respect to FIG. 2A.

In FIG. 2C, the basic element

illustrated in FIG. 2B is replaced by a basic element

. Likewise, the basic element o key may be intuitively recognized as theletter

 or a semicircle of the letter b or p.

FIG. 4 is a diagram for describing a method of assigning five main basicelements

411,

413,

415,

417, and † 419 on a keypad 420, according to an embodiment of thepresent invention.

Initially, all of the illustrated letters a, b, c, d, i, l, p, q, and tmay be formed by using a shape 410 illustrated at the center of FIG. 4.Also, the method corresponds to the order or direction of writing theletters a, b, c, d, i, l, p, q, and t. The basic elements

411,

413,

415,

417, and † 419 of the shape 410 are scattered and assigned on the keypad420.

On the keypad 420, a central horizontal line 421 may be assumed tocorrespond to the third line, which is used as the reference line forwriting small letters, from among four lines. Here, the letters a, b, c,d, i, l, p, q, and t may be intuitively input by respectively pressingsequentially keys 421, 423, 425, 427, and 429. In particular, except forthe letters c, i, l, and t that may be input by pressing a single key,the letters a, b, d, p, and q may be input by sequentially pressing twoneighboring keys.

One who understands English to a certain degree would accurately knowwhere to draw a curve and a straight line to write English letters andthus may easily input small letters by combining the above keys 421,423, 425, 427, and 429 as if the letters are written with a pen. Also, awriting order is always from left to right and an order of pressingbasic elements corresponds to the writing order. For example, in FIG. 4,the letter q may be input by sequentially pressing the basic elements

423 and † 429 (423→429) so as to correspond to the writing order of theletter q.

After assigning the basic elements

411,

413,

415,

417, and † 419, the other basic elements have to be assigned. When theother basic elements are assigned, intuitiveness of inputting lettersand minimum key pressing order for inputting letters should also beconsidered.

FIG. 5 is a diagram for describing a method of assigning the other basicelements

501 and

503 on a keypad, according to an embodiment of the present invention.

As the other basic elements

501 and

503 are assigned, the letter g is input by sequentially pressing thebasic elements

423 and

503, and the letter h is input by sequentially pressing the basicelements

421 and

501. In this case, the key pressing order and direction correspond tothe writing order and direction, and keys to be pressed to input aletter are adjacent to each other.

FIG. 6 shows overall key pressing orders for inputting small letters ona keypad, according to an embodiment of the present invention.

As illustrated in FIG. 6, the letters a, b, d, g, h, k, p, q, and y maybe input by sequentially pressing two neighboring (including diagonallyneighboring) keys, and the letters c, e, f, i, j, l, n, o, t, u, and vmay be input by pressing a single key. According to a selection of auser, the letter b may be input by pressing a single key. Also, theletters m, v, w, and z may be input by repeatedly pressing a key. Fromamong the twenty six alphabet letters, only three letters r, s, and xare input by sequentially pressing non-neighboring keys. However, thekey pressing order and direction for inputting the letters r, s, and xcorrespond to order and direction for intuitively writing the letters r,s, and x.

In consideration of user's convenience, when a user desires to inputcapital letters, a small letter may be input and then an additionalfunction key may be pressed to change the small letter into a capitalletter, or an input mode may be toggled and changed from a small lettermode to a capital letter mode or vice versa by pressing the additionalfunction key.

FIG. 7 shows overall key dragging orders for inputting small letters ona keypad, according to an embodiment of the present invention.

If the keypad is of a touch type, an initial key may be touched and thena stylus pen that touches the initial key may be dragged to a subsequentkey according to the key pressing orders illustrated in FIG. 6 withouttaking the stylus pen off the keypad. A keypad apparatus may recognize akey on which an initial touch is sensed as the initial key, and a key onwhich the touch is terminated after dragging as the subsequent key. Forexample, in order to input the letter a, a

key that is assigned may be initially touched, and then a finger or astylus pen that touches the

key may be dragged to and then be taken off a

key.

In this case, the dragging method is also useful to sequentially presstwo non-neighboring keys. For example, as illustrated in FIG. 7, inorder to input the letter x, a finger may touch a

key, the finger may move on the l key, and the finger motion may end onthe

key. In this case, only the initially touched

key and the ultimately touched

key may be recognized to input an alphabet letter without recognizingthe intermediately passed

key as a pressed key.

If double touching of a key is required, a user may use one of aplurality of methods. For example, first, the key may be continuouslypressed for more than a predetermined period of time. Second, the keymay be dragged from left to right or from top to bottom. Alternatively,the key may be simply touched twice.

In more detail, when a

key is repeatedly touched to input the letter m, according to the abovesecond method, as illustrated in FIG. 7, the

key is dragged from left to right. Although the n key may be draggedfrom top to bottom, the dragging from left to right is appropriate inconsideration of writing intuitiveness.

According to the method illustrated in FIG. 6 or 7, various punctuationmarks may also be easily input. This function is not enabled on ageneral English keypad but is enabled on the keypad according to thepresent invention because basic elements formed by separating andsymbolizing strokes of letters are assigned on the keypad.

For example, sequential pressing of

and

may be recognized as an exclamation mark (!), sequential pressing of

and o may be recognized as a question mark (?), double pressing of

may be recognized as a period (.), double pressing of

may be recognized as a comma (,), and sequential pressing of

and

may be recognized as an at mark (@). In this manner, punctuation marksmay be directly input via the keypad according to the present inventionwithout using an additional special character keyboard or mode.

Also, in addition to the English letters, various other letters, e.g.,Spanish, German, French, and Portuguese letters, may also be easilyinput by using the keypad according to the present invention. Table 1shows variations in inputting other letters according to the number oftimes that a special key is pressed after an English letter is input.

TABLE 1 [a→A] 1^(st) 2^(nd) 3^(rd) 4^(th) a á A Á a e é E É e i í I Í io ó O Ó o u ú ü U u n ñ N Ñ n

However, the variations shown in Table 1 are only examples, and allletters with English equivalents may be input by repeatedly pressing aspecial key. For example, after the letter a is recognized, variationssuch as “á, ä, à, â, ã, å” may be displayed on a screen by repeatedlypressing a special key. Also, corresponding capital letters may also bedisplayed.

As another example, after the letter n is recognized, variations such as“ń,

, {hacek over (n)}, ñ, η” may be displayed on a screen by repeatedlypressing a special key. Also, corresponding capital letters may also bedisplayed.

Furthermore, in addition to Spanish, German, French, and Portugueseletters, Greek letters (α, β, γ, δ, ε, ζ, η, θ, ι, κ, λ, μ, ν, ξ, ∘, π,ρ, σ, τ,

, φ, χ, Ψ, and ω) similar to English letters may also be input by usingthe basic elements according to the present invention. In this case,Greek letters may be input in an English mode or by changing the modeinto a Greek mode. In order to input Greek letters, one or more of thebasic elements

,

,

,

,

,

,

, †,

, —, and o are sequentially pressed, and a Greek letter corresponding tothe sequentially pressed basic elements is determined. For example,sequential pressing of

,

, and

may be recognized as Greek letter α, sequential pressing of †,

, and

may be recognized as Greek letter β, sequential pressing of — and

may be recognized as Greek letter γ, sequential pressing of

and

as Greek letter δ, double pressing of

may be recognized as Greek letter ε, sequential pressing of — and

may be recognized as Greek letter ζ, sequential pressing of

and † may be recognized as Greek letter

, sequential pressing of o and — may be recognized as Greek letter θ,single pressing of

as may be recognized Greek letter τ, sequential pressing of

and

may be recognized as Greek letter κ, sequential pressing of

and

may be recognized as Greek letter λ, sequential pressing of † and

may be recognized as Greek letter μ, double pressing of

may be recognized as Greek letter ν, sequential pressing of —,

, and

may be recognized as Greek letter ξ, double pressing of

as Greek letter ∘, sequential pressing of —,

, and

may be recognized as Greek letter π, sequential pressing of † and

may be recognized as Greek letter ρ, sequential pressing of

and — may be recognized as Greek letter σ, sequential pressing of — and

may be recognized as Greek letter τ, sequential pressing of — and

may be recognized as Greek letter

, sequential pressing of o and

may be recognized as Greek letter φ, sequential pressing of

and

may be recognized as Greek letter χ, sequential pressing of

and † may be recognized as Greek letter Ψ, and sequential pressing of

and

may be recognized as Greek letter ω, thereby inputting and displayingGreek letters on a screen.

Also, Russian letters (a,

, B, r,

, e, ë,

, 3,

, k,

, M, H, o,

, p, c, T, y,

, x,

bl, b, b,

,

, and

) may be input by using the basic elements of the present invention.

When various letters are input by using a keypad on which the basicelements of the present invention are assigned, the letters may beintuitively input and thus key assignment may be easily learned andmemorized. Furthermore, the number of key pressings or touches may bequite efficiently reduced. Accordingly, the keypad of the presentinvention may be applied to teaching or game tools for teaching thealphabet to small children, as well as mobile communication terminalssuch as cellular phones. Children who start to recognize and learn thealphabet may acquire a method of creating letters by combining the basicelements according to the present invention, instead of directlymemorizing letters such as A, B, and C. Thus, the present invention maybe useful for learning and playing letter games.

Also, if English letters or other letters are input by using a keypad onwhich the basic elements of the present invention are assigned, thenumber of key pressings may be reduced in comparison to a typicalkeypad. For example, it is assumed that a user sends the followingmessage by using a short message service (SMS).

“John, call me right now we r waiting for u at t mart”

In order to input the above sentence by using the phone-key keypadillustrated in FIG. 1, the keys should be pressed eighty-three times. Onthe other hand, if the keypad according to the present invention isused, the keys should be pressed only sixty-eight times excluding thecomma (,) and thus the number of key pressings may be about 82% of theprevious case. Moreover, since the keypad according to the presentinvention has an intuitive key assignment that can be easily memorized,a sentence may be easily input without even looking at a keypad of aterminal device.

FIG. 8 illustrates a cellular phone 810 including the keypad illustratedin FIG. 2A, according to an embodiment of the present invention.

As illustrated in FIG. 8, the keypad illustrated in FIG. 2A may beapplied to the cellular phone 810. In consideration of user'sconvenience, the keypad also has a typical input mode. The user mayselect the typical input mode or a stroke combination mode according tothe present invention. Although FIG. 8 illustrates a slide-type cellularphone, the keypad may also be applied to all cellular phones or mobiledevices of a folder type, a flip type, and a touch type.

FIGS. 9A through 9D illustrate various key assignments of basic elements

,

,

,

,

,

,

, †,

, —, and

on a keypad, according to embodiments of the present invention.

As described above in relation to FIG. 3, it is recommended not tochange the positions of the five main basic elements

,

,

,

, and †, which are respectively assigned to key numbers 2, 4, 5, 6, and8 in a cross shape, in consideration of user's convenience. However,these positions are merely recommended to provide an optimal inputcondition and may freely vary in consideration of user's convenience.

FIG. 9A shows an optimal key assignment on the keypad.

In FIG. 9A, the other basic elements

,

,

, and

are respectively assigned to key numbers 1, 3, 7, and 9 keys. This typeof key assignment is an optimal assignment because letters h, y, etc.,may be input by sequentially pressing two neighboring keys and a keypressing order and direction correspond to a writing order anddirection. The two remaining basic elements — and

may be appropriately assigned to the remaining keys of the keypad.However, since the basic element — is used to input the letter e that isthe most commonly used vowel, it may be more convenient to assign thebasic element — to the key number 0.

In the key assignment illustrated in FIG. 9A, the basic elements aresymmetric in shape. For example, the basic elements assigned to the keynumbers 1 and 3, the key numbers 4 and 6, and the key numbers 7 and 9are mirror-symmetric or 180°-symmetric in shape such that the keyassignment illustrated in FIG. 9A is highly design-competitive.

The key assignments illustrated in FIGS. 9B through 9D are alsopossible.

In FIGS. 9B through 9D, the positions of the basic elements

,

,

, and

respectively assigned to the key numbers 1, 3, 7, and 9 in the keyassignment illustrated in FIG. 9A are appropriately changed. However,the key assignments illustrated in FIGS. 9B through 9D are only examplesof modified key assignments and the key assignment of the basic elements

,

,

, and

may have a larger number of modifications.

FIG. 10 illustrates a keypad for identifying subsequent basic elementsthat are available to be pressed after an initial basic element ispressed, according to an embodiment of the present invention.

When a user inputs a letter by pressing two keys, an initial basicelement is pressed and then a subsequent basic element is pressed. Inthis case, if subsequent basic elements that are available to be pressedafter the initial basic element is pressed are automatically identifiedon the keypad, the user may press the subsequent basic element moreconveniently.

In FIG. 10, it is assumed that the user presses a basic element

1010 represented in a shaded manner. If the basic element

1010 is pressed, the letter c may be input without additionally pressinganother basic element, or the letters d, a, g, or q may be input byadditionally pressing a basic element

,

,

, or † 1020. In this case, since a space key 1030 may be pressed toconfirm input of the letter c, in a broad sense, the space key 1030 mayalso be a basic element that is available to be pressed after the basicelement

1010 is pressed.

If the basic element

1010 is pressed, a keypad apparatus identifies the basic elements

,

,

, and † 1020 from other non-available basic elements such that the usermay easily recognize that only the basic elements

,

,

, and † 1020 are available to be subsequently pressed. Various methodsmay be used to identify available basic elements from othernon-available basic elements. For example, although the cellular phone810 illustrated in FIG. 8 may not easily identify keys, if a backlightunit is included to light trims of individual keys of the availablebasic elements as represented by dashed squares in FIG. 10, theavailable basic elements may be visually identified from othernon-available basic elements. Alternatively, numbers or the availablebasic elements on the individual keys may be lit by the backlight unit.

If the keypad is a touchpad, the available basic elements may beidentified more easily. Since touch keys are graphically displayed on ascreen, if the basic element

1010 is pressed, the basic elements

,

,

, and † 1020 that are available to be subsequently pressed may bedisplayed by using a different graphic so as to be easily recognized bythe user. The different graphic may be obtained by using, for example, adifferent color, an inversed color, or a flickering effect.

After the basic element

1010 is initially pressed, if any of the basic elements

,

,

, and † 1020 is not pressed to input the letter d, a, g, or q, and ifanother basic element is pressed, input of the letter c may beconfirmed.

When letters are input by pressing the basic elements, double keypressing for each letter is convenient. For example, single key pressingis followed by a pressing of a space bar. However, this method increasesthe number of key pressings.

In order to solve the above problem, the following method may be used.

A user may press an initial basic element for a short time and asubsequent basic element for a long time. In order to input a letter bypressing a single key, the initial basic element is pressed for a longtime. For example, in order to input “change”, the order of pressingbasic elements is

—, and the periods of time for pressing them are -*-*--*-- (* representsa short time and - represents a long time).

FIG. 11 is a block diagram of a keypad apparatus 1100 according to anembodiment of the present invention.

The keypad apparatus 1100 includes a keypad 1110, a visual conversionunit 1120, a time check unit 1130, a control unit 1140, and a displayunit 1150. The keypad 1110 may be of a button type or a touch type andincludes a plurality of keys to which basic elements

,

,

,

,

,

,

†,

, —, and

obtained by separating and symbolizing strokes of letters are assigned.

As described above in relation to FIG. 10, if two keys are sequentiallypressed, the visual conversion unit 1120 visually identifies from othernon-available keys subsequent keys that are available to be pressed toinput letters after an initial key is pressed. As described above inrelation to FIG. 10, the visual identification may be performed by usingany visual identification method such as a method using a backlight, adifferent color, or an inversed color.

The time check unit 1130 measures a time taken for a key pressing todetermine whether the key pressing is the final one. For example, if twokeys are sequentially pressed and if a second key is pressed for a longtime in comparison to a short time for pressing a first key, the timecheck unit 1130 recognizes the pressing of the second key as the finalone. If a single key is pressed and if the first key is pressed for along time, the time check unit 1130 may recognize the pressing of thefirst key as the final one. A user may set the short time and the longtime.

The control unit 1140 controls data or processes of the keypad 1110, thevisual conversion unit 1120, and the time check unit 1130, and displaysletters input by pressing keys on the display unit 1150.

In addition, the control unit 1140 may convert the input letters into aphone number. For example, in the USA, an advertisement is made in manycases by providing a phone number corresponding to advertizing text,e.g., a company or product name, input by using the phone-key keypadillustrated in FIG. 1. For example, in the case of a toy company “ALLTOYS”, their phone number may be determined as2(A)5(L)5(L)-8(T)6(O)9(Y)7(S) such that this phone number is pressed byselecting the company name on the phone-key keypad. If astroke-combining keypad according to the present invention is used, thephone number may not be directly pressed as described above. Instead,letters corresponding to the company name are input on the keypad andthen the input letters are recognized as numbers. Since the keypadaccording to the present invention is basically used to input smallletters, “all toys” is input as the company name. Then, if a ‘send’button is pressed, the control unit 1140 matches the letter a to number2, the letter l to number 5, the letter t to number 8, the letter o tonumber 6, the letter y to number 9, and the letter s to number 7, suchthat the user may automatically call the number 255-8697.

Also, the above-described method and apparatus may also be useful toinput Chinese or Japanese characters. Chinese is an ideogram-basedlanguage and it is not possible to separately assign all Chinesecharacters to keys on a keyboard. Accordingly, the pronunciation of aChinese character may be input by using English letters and then theinput English letters may be automatically or manually changed into theChinese character corresponding to the pronunciation.

For example, if “shang” is input, an algorithm may display variousChinese characters corresponding to the pronunciation, e.g.,

and a, on a screen automatically or by pressing a predetermined key.Then, a user may select one of the various Chinese characters. Sincethis method eventually uses English letters, Chinese characters may alsobe efficiently input by using the method according to the presentinvention.

The same principle applies to Japanese characters. Although Japanese isa phonogram-based language, and it is not easy to separately assign allthe fifty Japanese characters including hiragana and katakana charactersto keys on a general keyboard. In this case, the pronunciation of aJapanese character may be input by using English letters and then theinput English letters may be changed into the Japanese charactercorresponding to the pronunciation. For example, if “tsu” is input, theJapanese character

may be input automatically or by pressing an additional key. Japanesecharacters may also be rapidly and easily input by using the methodaccording to the present invention.

While the present invention has been particularly shown and describedwith reference to exemplary embodiments thereof, it will be understoodby one of ordinary skill in the art that various changes in form anddetails may be made therein without departing from the spirit and scopeof the present invention as defined by the following claims.

What is claimed is:
 1. A method of inputting letters, the method comprising: pressing one of or sequentially pressing two of basic elements

,

,

,

,

,

,

, †,

, —, and

obtained by separating and symbolizing strokes of letters; determining a letter corresponding to the pressed basic element or the sequentially pressed basic elements; and displaying the determined letter, wherein the basic element

is used as a center element, and wherein the basic elements

, †,

, and

are respectively assigned directly to top, bottom, left, and right sides of the center element.
 2. The method of claim 1, wherein the displaying of the determined letter comprises at least one of: recognizing sequential pressing of the basic elements

and

as the letter a; recognizing sequential pressing of the basic elements

and

as the letter b; recognizing single pressing of the basic element

as the letter c; recognizing sequential pressing of the basic elements

and

as the letter d; recognizing single pressing of the basic element — as the letter e; recognizing single pressing of the basic element

as the letter f; recognizing sequential pressing of the basic elements

and

as the letter g; recognizing sequential pressing of the basic elements

and

as the letter h; recognizing single pressing of the basic element

as the letter i; recognizing single pressing of the basic element

as the letter j; recognizing sequential pressing of the basic elements

and

as the letter k; recognizing single pressing of the basic element

as the letter l; recognizing double pressing of the basic element

as the letter m; recognizing single pressing of the basic element

as the letter n; recognizing single pressing of the basic element

as the letter o; recognizing sequential pressing of the basic elements † and

as the letter p; recognizing sequential pressing of the basic elements

and † as the letter q; recognizing sequential pressing of the basic element

and — as the letter r; recognizing sequential pressing of the basic elements

and

as the letter s; recognizing single pressing of the basic element † as the letter t; recognizing single pressing of the basic element

as the letter u; recognizing double pressing of the basic element

as the letter v; recognizing double pressing of the basic element

as the letter w; recognizing sequential pressing of the basic elements

and

as the letter x; recognizing sequential pressing of the basic element

and

as the letter y; and recognizing double pressing of the basic element — as the letter z.
 3. The method of claim 2, wherein the displaying of the determined letter further comprises at least one of: recognizing single pressing of the basic element

as the letter b; recognizing sequential pressing of the basic elements

and — as the letter f; recognizing double pressing of the basic element

as the letter s; recognizing sequential pressing of the basic elements — and

as the letter t; recognizing sequential pressing of the basic elements

and

as alphabet y; and recognizing sequential pressing of the basic element

and † as the letter y.
 4. The method of claim 2, wherein the letters a, b, d, k, p, and q are recognized by sequentially pressing two neighboring keys in the same direction and order as the writing direction and order thereof.
 5. The method of claim 4, wherein the basic elements

and

are respectively assigned to left and right sides of the basic element

, wherein the basic elements

and

are respectively assigned to left and right sides of the basic element †, and wherein the letters h, g, and y are recognized by sequentially pressing two neighboring keys in the same direction and order as the writing direction and order thereof.
 6. The method of claim 4, wherein the basic elements

and

are respectively assigned to left and right sides of the basic element

, wherein the basic elements

and

are respectively assigned to left and right sides of the basic element †, and wherein the letters g and y are recognized by sequentially pressing two neighboring keys.
 7. The method of claim 2, wherein a first key is comprised in addition to keys to which the basic elements

,

,

,

,

,

,

, †,

, —, and o are assigned, and wherein subsequent key pressing of the first key determines each letter after a single key is pressed.
 8. The method of claim 2, wherein a second key is comprised in addition to keys to which the basic elements

,

,

,

,

,

,

, †,

, —, and o are assigned, wherein, if the second key is repeatedly pressed after the letter a is recognized, the letter a is sequentially changed into at least one of “A, á, Á, ä, Ä”, wherein, if the second key is repeatedly pressed after the letter e is recognized, the letter e is sequentially changed into at least one of “E, é, É”, wherein, if the second key is repeatedly pressed after the letter i is recognized, the letter i is sequentially changed into at least one of “I, í, Í”, wherein, if the second key is repeatedly pressed after the letter o is recognized, the letter o is sequentially changed into at least one of “O, ó, Ó, ö, Ö”, wherein, if the second key is repeatedly pressed after the letter u is recognized, the letter u is sequentially changed into at least one of “U, ú, Ú, ü, Ü”, and wherein, if the second key is repeatedly pressed after the letter n is recognized, the letter n is sequentially changed into at least one of “N, ñ, Ñ”.
 9. The method of claim 2, wherein sequential pressing of the basic elements

and

is recognized as an exclamation mark (!); wherein sequential pressing of the basic elements

and

is recognized as a question mark (?); wherein double pressing of the basic element

is recognized as a period (.); wherein double pressing of the basic element

is recognized as a comma (,); and wherein sequential pressing of the basic elements

and

is recognized as an at mark (@).
 10. The method of claim 2, wherein subsequent basic elements that are available to be pressed to input letters after an initial basic element is pressed are visually identified from other non-available basic elements.
 11. The method of claim 3, wherein subsequent basic elements that are available to be pressed to input letters after an initial basic element is pressed are visually identified from other non-available basic elements.
 12. The method of claim 10 or 11, wherein the available basic elements are visually identified by using at least one of a backlight, an inversed color, and a different color.
 13. The method of claim 1, wherein a touchpad apparatus is formed by using the basic element

as a center element, respectively assigning the basic elements I, †,

, and

to top, bottom, left and right sides of the center element, respectively assigning the basic elements u and n to left and right sides of the basic element

, and respectively assigning the basic elements

and

to left and right sides of the basic element †, and wherein the touchpad apparatus recognizes: dragging from the basic element

to the basic element

as the letter a; dragging from the basic element

to the basic element

as the letter b; single touching of the basic element

as the letter c; dragging from the basic element

to the basic element

as the letter d; single touching of the basic element — as the letter e; single touching of the basic element

as the letter f; dragging from the basic element

to the basic element

as the letter g; dragging from the basic element

to the basic element

as the letter h; single touching of the basic element

as the letter i; single touching of the basic element

as the letter j; dragging from the basic element

to the basic element

as the letter k; single touching of the basic element

as the letter l; double touching of the basic element

as the letter m; single touching of the basic element

as the letter n; single touching of the basic element

as the letter o; dragging from the basic element † to the basic element

as the letter p; dragging from the basic element

to the basic element † as the letter q; dragging from the basic element

to the basic element

via the basic element as the letter s; single touching of the basic element † as the letter t; single touching of the basic element

as the letter u; double touching of the basic element

as the letter v; double touching of the basic element

as the letter w; dragging from the basic element

to the basic element

via the basic element as the letter x; dragging from the basic element

to the basic element

as the letter y; and double touching of the basic element — as the letter z.
 14. The method of claim 13, wherein the basic element — is assigned to a bottom side of the basic element †, and wherein the touchpad apparatus recognizes dragging from the basic element

to the basic element — via the basic element † as the letter r.
 15. The method of claim 13, wherein the touchpad apparatus recognizes: left-to-right or top-to-bottom dragging on the basic element

as the letter m; left-to-right or top-to-bottom dragging on the basic element

as the letter v; left-to-right or top-to-bottom dragging on the basic element

as the letter w; and left-to-right or top-to-bottom dragging on the basic element — as the letter z.
 16. A keypad apparatus for inputting letters, the keypad apparatus comprising a plurality of keys to which basic elements

,

,

,

,

,

,

, †,

, —, and

obtained by separating and symbolizing strokes of letters are separately assigned, and the keypad apparatus recognizing letters by using a method comprising at least one of: recognizing sequential pressing of the basic elements

and l as the letter a; recognizing sequential pressing of the basic elements

and

as the letter b; recognizing single pressing of the basic element

as the letter c; recognizing sequential pressing of the basic elements

and

as alphabet d; recognizing single pressing of the basic element — as the letter e; recognizing single pressing of the basic element

as the letter f; recognizing sequential pressing of the basic elements

and

as the letter g; recognizing sequential pressing of the basic elements

and

as the letter h; recognizing single pressing of the basic element

as the letter i; recognizing single pressing of the basic element

as the letter j; recognizing sequential pressing of the basic elements

and

as the letter k; recognizing single pressing of the basic element

as the letter l; recognizing double pressing of the basic element

as the letter m; recognizing single pressing of the basic element

as the letter n; recognizing single pressing of the basic element

as the letter o; recognizing sequential pressing of the basic elements † and

as the letter p; recognizing sequential pressing of the basic elements

and † as the letter q; recognizing sequential pressing of the basic element

and — as the letter r; recognizing sequential pressing of the basic elements

and

as the letter s; recognizing single pressing of the basic element † as the letter t; recognizing single pressing of the basic element

as the letter u; recognizing double pressing of the basic element

as the letter v; recognizing double pressing of the basic element

as the letter w; recognizing sequential pressing of the basic elements

and

as the letter x; recognizing sequential pressing of the basic element

and

as the letter y; and recognizing double pressing of the basic element — as the letter z, wherein the basic element

is used as a center element, and wherein the basic element

, †,

, and

are respectively assigned to top, bottom, left and right sides of the center element.
 17. The keypad apparatus of claim 16, wherein the letters a, b, d, k, p, and q are recognized by sequentially pressing two neighboring keys in the same direction and order as the writing direction and order thereof.
 18. The keypad apparatus of claim 17, wherein the basic elements

and

are respectively assigned to left and right sides of the basic element

, wherein the basic elements

and

are respectively assigned to left and right sides of the basic element †, and wherein the letters h, g, and y are recognized by sequentially pressing two neighboring keys in the same direction and order as the writing direction and order thereof.
 19. The keypad apparatus of claim 16, wherein the keypad apparatus is a touchpad apparatus.
 20. The keypad apparatus of claim 17, wherein sequential pressing of the basic elements

and

is recognized as an exclamation mark (!); wherein sequential pressing of the basic elements

and

is recognized as a question mark (?); wherein double pressing of the basic element

is recognized as a period (.); wherein double pressing of the basic element

is recognized as a comma (,); and wherein sequential pressing of the basic elements

and

is recognized as an at mark (@).
 21. The keypad apparatus of claim 16, further comprising a first key in addition to the keys to which the basic elements

,

,

,

,

,

,

, †,

, —, and

are assigned, wherein, if the first key is pressed after a small letter is recognized, the small letter is changed into a capital letter.
 22. The keypad apparatus of claim 16, further comprising a first key in addition to the keys to which the basic elements

,

,

,

,

,

,

, †,

, —, and

are assigned, wherein the first key is used to select a small letter mode or a capital letter mode.
 23. The keypad apparatus of claim 16, further comprising an additional key in addition to the keys to which the basic elements

,

,

,

,

,

,

, †,

, —, and

are assigned, wherein double key pressing is determined for each letter by pressing the additional key after a single key is pressed.
 24. The keypad apparatus of claim 16, further comprising a visual conversion unit for visually identifying from other non-available keys subsequent keys that are available to be pressed to input letters after an initial key is pressed, if two keys are sequentially pressed.
 25. The keypad apparatus of claim 16, further comprising a time check unit for identifying a short time and a long time for sequentially pressing keys such that the short time and the long time are respectively determined as periods of time for pressing initial and subsequent keys.
 26. The method of claim 11, wherein the available basic elements are visually identified by using at least one of a backlight, an inversed color, and a different color.
 27. The keypad apparatus of claim 17, wherein the keypad apparatus is a touchpad apparatus.
 28. The keypad apparatus of claim 18, wherein the keypad apparatus is a touch pad apparatus. 